The present invention relates to an axial bearing device having an annular electrical sheet arrangement in which the individual sheets protrude radially outward, and an electrical coil which is inserted into the electrical sheet arrangement in order to generate a magnetic field in the electrical sheet arrangement.
Active, magnetic axial bearings are used in order to set defined spacings between two objects in contactless fashion. The basic construction of such an axial bearing can be seen in FIG. 1. In the example a shaft 1 is mounted in axial fashion. A steel disk 2 is attached concentrically on the shaft 1. In addition to the steel disk 2 the axial bearing arrangement here has two annular electromagnets 3, 4 (here also referred to as axial bearing devices) which are arranged on both sides of the steel disk 2 coaxially therewith and with the shaft 1. While the electromagnets 3 and 4 are static and are attached for example on the housing of an electrical machine, the shaft including the steel disk 2 rotates in the interior of the two electromagnets 3, 4.
The electromagnets 3, 4 exert forces on soft magnetic materials such as the steel disk 2. When the electromagnets 3, 4 are suitably controlled, the steel disk 2 can be held in contactless fashion at a defined axial position between the electromagnets 3 and 4.
The electromagnets 3, 4 are as a rule constructed using torroidal cores which are arranged in a groove in an iron support. The iron support is usually of solid construction. In solidly constructed supports field changes result in eddy currents which in turn produce opposing fields. The controllability of the magnetic bearings is thereby degraded.
Eddy currents are reduced in a known manner through lamination of the support iron. The lamination of axial bearing supports is known from the publication DE 691 03 756 T2 where the stator and rotor components of a magnetic thrust bearing are described with each having a laminated design. The lamination sheets are curved such that their tips lie in a common cylindrical plane. In addition, side edges abutting one another of the lamination sheets likewise lie in common planes which are arranged perpendicular to the axis of rotation.